Cellulose/Poly(vinyl alcohol) Blends. 1. Influence of Miscibility and Water Content on Relaxations

Abstract

This contribution is concerned with cellulose/poly(vinyl alcohol) blends, and it concentrates on the influence of miscibility and the presence of water on relaxations. The blends were characterized by small and wide angle X-ray scattering as well as by dielectric and dynamic mechanical spectroscopy. They display no residual crystallinity and are characterized by a molecular mixing of the components with microheterogeneities on a nanometer scale. The water is bonded yet mobile. A temperature increase leads to an enhanced mobility of the water as well as to the onset of main-chain rearrangements and of decomposition. A secondary relaxation occurs in all blends: the relaxation behavior is similar for the blends and the pure cellulose. A major result is that the presence of water influences the relaxation in the blends more strongly than the presence of the blend component poly(vinyl alcohol).